1. Field of the Invention
The present invention relates to an InfiniBand™ router configured for sending and receiving data packets in an InfiniBand™ network and, more particularly, to a router which maps Ethernet (IEEE 802.1P) LAN priorities to a virtual lane of an InfiniBand™ network
2. Background Art
Networking technology has encountered improvements in server architectures and design with a goal toward providing servers that are more robust and reliable in mission critical networking applications. In particular, the use of servers for responding to client requests has resulted in a necessity that servers have an extremely high reliability to ensure that the network remains operable. Hence, there has been a substantial concern about server reliability, accessibility, and serviceability.
In addition, processors used in servers have encountered substantial improvements, where the microprocessor speed and bandwidth have exceeded the capacity of the connected input/out (I/O) buses, limiting the server throughput to the bus capacity. Accordingly, different server standards have been proposed in an attempt to improve server performance in terms of addressing, processor clustering, and high-speed I/O.
These different proposed server standards led to the development of the InfiniBand™ Architecture Specification, (Release 1.0), adopted by the InfiniBand™ Trade Association. The InfiniBand™ Architecture Specification specifies a high-speed networking connection between central processing units, peripherals, and switches inside a server system. Hence, the term “InfiniBand™ network” refers to a network within a server system. The InfiniBand™ Architecture Specification specifies both I/O operations and interprocessor communications (IPC).
A particular feature of InfiniBand™ Architecture Specification is the proposed implementation in hardware of the transport layer services present in existing networking protocols, such as TCP/IP based protocols. The hardware-based implementation of transport layer services provides the advantage of reducing processing requirements of the central processing unit (i.e., “offloading”), hence offloading the operating system of the server system.
The InfiniBand™ Architecture Specification describes a network architecture, illustrated in FIG. 1. The network 10 includes nodes 11, each having an associated channel adapter 12 or 14. For example, the computing node 11a includes processors 16 and a host channel adapter (HCA) 12; the destination target nodes 11b and 11c include target channel adapters 14a and 14b, and target devices (e.g., peripherals such as Ethernet bridges or storage devices) 18a and 18b, respectively. The network 10 also includes routers 20, and InfiniBand™ switches 22.
Channel adapters operate as interface devices for respective server subsystems (i.e., nodes). For example, host channel adapters (HCAs) 12 are used to provide the computing node 11a with an interface connection to the InfiniBand™ network 10, and target channel adapters (TCAs) 14 are used to provide the destination target nodes 11b and 11c with an interface connection to the InfiniBand™ network. Host channel adapters 12 may be connected to a memory controller 24 as illustrated in FIG. 1. Host channel adapters 12 implement the transport layer using a virtual interface referred to as the “verbs” layer that defines in the manner in which the processor 16 and the operating system communicate with the associated HCA 12: verbs are data structures (e.g., commands) used by application software to communicate with the HCA. Target channel adapters 14, however, lack the verbs layer, and hence communicate with their respective devices 18 according to the respective device protocol (e.g., PCI, SCSI, etc.).
Presently, when an Ethernet frame containing layer 2 priorities is received at an InfiniBand™ network, there is no mapping support in the InfiniBand™ network for layer 2 layer priorities and the packet is simply sent by a router as a raw datagram. Thus, the application layer priorities of the packet are not retained.